Avast Free Antivirus 17.3.2291 Build 17.3.3443.0

How do I figure out what is causing the yellow exclamation-warning on my Avast Free Icon in the system tray. It has not always been there, and no, I recently did not install any new program. Any automatic or non-automatic updates on several programs were done, no record of that.
In the smart scan Avast complains about Comodo Firewall, but that was there already before the excl.mark appeared.
Any ideas?

Marcel

You are using a old(er) version of avast.
Perform a clean installation of the latest version and check if the problem is solved.

Thanks for your reply.
I know it is an old version but reading all the problems with 17.4.2294 I better wait a while.
That’s why I asked where to look for the cause of the problem, maybe I can solve it in this old version.

Marcel